﻿using System;
using System.Collections;
using System.Globalization;
using System.IO;
using System.Text;

// 
// System.Web.HttpUtility
//
// Authors:
//   Patrik Torstensson (Patrik.Torstensson@labs2.com)
//   Wictor Wilén (decode/encode functions) (wictor@ibizkit.se)
//   Tim Coleman (tim@timcoleman.com)
//   Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
//   12/30/03 -- Modified by Kevin Z Grey (kzgrey@ntplx.net) to compile 
//   on the .NET Compact Framework
//
// 11/08/09 -- Changed namespace for Avian Play
//

namespace System.Web
{
  public sealed class HttpUtility
  {

    #region Fields

    const string _hex = "0123456789ABCDEF";
    const string _chars = "<>;:.?=&@*+%/\\";
    static Hashtable entities;

    #endregion // Fields

    #region Constructors

    static HttpUtility()
    {
      // Build the hash table of HTML entity references.  This list comes
      // from the HTML 4.01 W3C recommendation.
      entities = new Hashtable();
      entities.Add("nbsp", '\u00A0');
      entities.Add("iexcl", '\u00A1');
      entities.Add("cent", '\u00A2');
      entities.Add("pound", '\u00A3');
      entities.Add("curren", '\u00A4');
      entities.Add("yen", '\u00A5');
      entities.Add("brvbar", '\u00A6');
      entities.Add("sect", '\u00A7');
      entities.Add("uml", '\u00A8');
      entities.Add("copy", '\u00A9');
      entities.Add("ordf", '\u00AA');
      entities.Add("laquo", '\u00AB');
      entities.Add("not", '\u00AC');
      entities.Add("shy", '\u00AD');
      entities.Add("reg", '\u00AE');
      entities.Add("macr", '\u00AF');
      entities.Add("deg", '\u00B0');
      entities.Add("plusmn", '\u00B1');
      entities.Add("sup2", '\u00B2');
      entities.Add("sup3", '\u00B3');
      entities.Add("acute", '\u00B4');
      entities.Add("micro", '\u00B5');
      entities.Add("para", '\u00B6');
      entities.Add("middot", '\u00B7');
      entities.Add("cedil", '\u00B8');
      entities.Add("sup1", '\u00B9');
      entities.Add("ordm", '\u00BA');
      entities.Add("raquo", '\u00BB');
      entities.Add("frac14", '\u00BC');
      entities.Add("frac12", '\u00BD');
      entities.Add("frac34", '\u00BE');
      entities.Add("iquest", '\u00BF');
      entities.Add("Agrave", '\u00C0');
      entities.Add("Aacute", '\u00C1');
      entities.Add("Acirc", '\u00C2');
      entities.Add("Atilde", '\u00C3');
      entities.Add("Auml", '\u00C4');
      entities.Add("Aring", '\u00C5');
      entities.Add("AElig", '\u00C6');
      entities.Add("Ccedil", '\u00C7');
      entities.Add("Egrave", '\u00C8');
      entities.Add("Eacute", '\u00C9');
      entities.Add("Ecirc", '\u00CA');
      entities.Add("Euml", '\u00CB');
      entities.Add("Igrave", '\u00CC');
      entities.Add("Iacute", '\u00CD');
      entities.Add("Icirc", '\u00CE');
      entities.Add("Iuml", '\u00CF');
      entities.Add("ETH", '\u00D0');
      entities.Add("Ntilde", '\u00D1');
      entities.Add("Ograve", '\u00D2');
      entities.Add("Oacute", '\u00D3');
      entities.Add("Ocirc", '\u00D4');
      entities.Add("Otilde", '\u00D5');
      entities.Add("Ouml", '\u00D6');
      entities.Add("times", '\u00D7');
      entities.Add("Oslash", '\u00D8');
      entities.Add("Ugrave", '\u00D9');
      entities.Add("Uacute", '\u00DA');
      entities.Add("Ucirc", '\u00DB');
      entities.Add("Uuml", '\u00DC');
      entities.Add("Yacute", '\u00DD');
      entities.Add("THORN", '\u00DE');
      entities.Add("szlig", '\u00DF');
      entities.Add("agrave", '\u00E0');
      entities.Add("aacute", '\u00E1');
      entities.Add("acirc", '\u00E2');
      entities.Add("atilde", '\u00E3');
      entities.Add("auml", '\u00E4');
      entities.Add("aring", '\u00E5');
      entities.Add("aelig", '\u00E6');
      entities.Add("ccedil", '\u00E7');
      entities.Add("egrave", '\u00E8');
      entities.Add("eacute", '\u00E9');
      entities.Add("ecirc", '\u00EA');
      entities.Add("euml", '\u00EB');
      entities.Add("igrave", '\u00EC');
      entities.Add("iacute", '\u00ED');
      entities.Add("icirc", '\u00EE');
      entities.Add("iuml", '\u00EF');
      entities.Add("eth", '\u00F0');
      entities.Add("ntilde", '\u00F1');
      entities.Add("ograve", '\u00F2');
      entities.Add("oacute", '\u00F3');
      entities.Add("ocirc", '\u00F4');
      entities.Add("otilde", '\u00F5');
      entities.Add("ouml", '\u00F6');
      entities.Add("divide", '\u00F7');
      entities.Add("oslash", '\u00F8');
      entities.Add("ugrave", '\u00F9');
      entities.Add("uacute", '\u00FA');
      entities.Add("ucirc", '\u00FB');
      entities.Add("uuml", '\u00FC');
      entities.Add("yacute", '\u00FD');
      entities.Add("thorn", '\u00FE');
      entities.Add("yuml", '\u00FF');
      entities.Add("fnof", '\u0192');
      entities.Add("Alpha", '\u0391');
      entities.Add("Beta", '\u0392');
      entities.Add("Gamma", '\u0393');
      entities.Add("Delta", '\u0394');
      entities.Add("Epsilon", '\u0395');
      entities.Add("Zeta", '\u0396');
      entities.Add("Eta", '\u0397');
      entities.Add("Theta", '\u0398');
      entities.Add("Iota", '\u0399');
      entities.Add("Kappa", '\u039A');
      entities.Add("Lambda", '\u039B');
      entities.Add("Mu", '\u039C');
      entities.Add("Nu", '\u039D');
      entities.Add("Xi", '\u039E');
      entities.Add("Omicron", '\u039F');
      entities.Add("Pi", '\u03A0');
      entities.Add("Rho", '\u03A1');
      entities.Add("Sigma", '\u03A3');
      entities.Add("Tau", '\u03A4');
      entities.Add("Upsilon", '\u03A5');
      entities.Add("Phi", '\u03A6');
      entities.Add("Chi", '\u03A7');
      entities.Add("Psi", '\u03A8');
      entities.Add("Omega", '\u03A9');
      entities.Add("alpha", '\u03B1');
      entities.Add("beta", '\u03B2');
      entities.Add("gamma", '\u03B3');
      entities.Add("delta", '\u03B4');
      entities.Add("epsilon", '\u03B5');
      entities.Add("zeta", '\u03B6');
      entities.Add("eta", '\u03B7');
      entities.Add("theta", '\u03B8');
      entities.Add("iota", '\u03B9');
      entities.Add("kappa", '\u03BA');
      entities.Add("lambda", '\u03BB');
      entities.Add("mu", '\u03BC');
      entities.Add("nu", '\u03BD');
      entities.Add("xi", '\u03BE');
      entities.Add("omicron", '\u03BF');
      entities.Add("pi", '\u03C0');
      entities.Add("rho", '\u03C1');
      entities.Add("sigmaf", '\u03C2');
      entities.Add("sigma", '\u03C3');
      entities.Add("tau", '\u03C4');
      entities.Add("upsilon", '\u03C5');
      entities.Add("phi", '\u03C6');
      entities.Add("chi", '\u03C7');
      entities.Add("psi", '\u03C8');
      entities.Add("omega", '\u03C9');
      entities.Add("thetasym", '\u03D1');
      entities.Add("upsih", '\u03D2');
      entities.Add("piv", '\u03D6');
      entities.Add("bull", '\u2022');
      entities.Add("hellip", '\u2026');
      entities.Add("prime", '\u2032');
      entities.Add("Prime", '\u2033');
      entities.Add("oline", '\u203E');
      entities.Add("frasl", '\u2044');
      entities.Add("weierp", '\u2118');
      entities.Add("image", '\u2111');
      entities.Add("real", '\u211C');
      entities.Add("trade", '\u2122');
      entities.Add("alefsym", '\u2135');
      entities.Add("larr", '\u2190');
      entities.Add("uarr", '\u2191');
      entities.Add("rarr", '\u2192');
      entities.Add("darr", '\u2193');
      entities.Add("harr", '\u2194');
      entities.Add("crarr", '\u21B5');
      entities.Add("lArr", '\u21D0');
      entities.Add("uArr", '\u21D1');
      entities.Add("rArr", '\u21D2');
      entities.Add("dArr", '\u21D3');
      entities.Add("hArr", '\u21D4');
      entities.Add("forall", '\u2200');
      entities.Add("part", '\u2202');
      entities.Add("exist", '\u2203');
      entities.Add("empty", '\u2205');
      entities.Add("nabla", '\u2207');
      entities.Add("isin", '\u2208');
      entities.Add("notin", '\u2209');
      entities.Add("ni", '\u220B');
      entities.Add("prod", '\u220F');
      entities.Add("sum", '\u2211');
      entities.Add("minus", '\u2212');
      entities.Add("lowast", '\u2217');
      entities.Add("radic", '\u221A');
      entities.Add("prop", '\u221D');
      entities.Add("infin", '\u221E');
      entities.Add("ang", '\u2220');
      entities.Add("and", '\u2227');
      entities.Add("or", '\u2228');
      entities.Add("cap", '\u2229');
      entities.Add("cup", '\u222A');
      entities.Add("int", '\u222B');
      entities.Add("there4", '\u2234');
      entities.Add("sim", '\u223C');
      entities.Add("cong", '\u2245');
      entities.Add("asymp", '\u2248');
      entities.Add("ne", '\u2260');
      entities.Add("equiv", '\u2261');
      entities.Add("le", '\u2264');
      entities.Add("ge", '\u2265');
      entities.Add("sub", '\u2282');
      entities.Add("sup", '\u2283');
      entities.Add("nsub", '\u2284');
      entities.Add("sube", '\u2286');
      entities.Add("supe", '\u2287');
      entities.Add("oplus", '\u2295');
      entities.Add("otimes", '\u2297');
      entities.Add("perp", '\u22A5');
      entities.Add("sdot", '\u22C5');
      entities.Add("lceil", '\u2308');
      entities.Add("rceil", '\u2309');
      entities.Add("lfloor", '\u230A');
      entities.Add("rfloor", '\u230B');
      entities.Add("lang", '\u2329');
      entities.Add("rang", '\u232A');
      entities.Add("loz", '\u25CA');
      entities.Add("spades", '\u2660');
      entities.Add("clubs", '\u2663');
      entities.Add("hearts", '\u2665');
      entities.Add("diams", '\u2666');
      entities.Add("quot", '\u0022');
      entities.Add("amp", '\u0026');
      entities.Add("lt", '\u003C');
      entities.Add("gt", '\u003E');
      entities.Add("OElig", '\u0152');
      entities.Add("oelig", '\u0153');
      entities.Add("Scaron", '\u0160');
      entities.Add("scaron", '\u0161');
      entities.Add("Yuml", '\u0178');
      entities.Add("circ", '\u02C6');
      entities.Add("tilde", '\u02DC');
      entities.Add("ensp", '\u2002');
      entities.Add("emsp", '\u2003');
      entities.Add("thinsp", '\u2009');
      entities.Add("zwnj", '\u200C');
      entities.Add("zwj", '\u200D');
      entities.Add("lrm", '\u200E');
      entities.Add("rlm", '\u200F');
      entities.Add("ndash", '\u2013');
      entities.Add("mdash", '\u2014');
      entities.Add("lsquo", '\u2018');
      entities.Add("rsquo", '\u2019');
      entities.Add("sbquo", '\u201A');
      entities.Add("ldquo", '\u201C');
      entities.Add("rdquo", '\u201D');
      entities.Add("bdquo", '\u201E');
      entities.Add("dagger", '\u2020');
      entities.Add("Dagger", '\u2021');
      entities.Add("permil", '\u2030');
      entities.Add("lsaquo", '\u2039');
      entities.Add("rsaquo", '\u203A');
      entities.Add("euro", '\u20AC');
    }

    public HttpUtility()
    {
    }

    #endregion // Constructors

    #region Methods

    public static void HtmlAttributeEncode(string s, TextWriter output)
    {
      output.Write(HtmlAttributeEncode(s));
    }

    public static string HtmlAttributeEncode(string s)
    {
      if (null == s)
        return null;

      StringBuilder output = new StringBuilder();

      foreach (char c in s)
        switch (c)
        {
          case '&':

            output.Append("&amp;");
            break;
          case '"':

            output.Append("&quot;");
            break;
          default:

            output.Append(c);
            break;
        }

      return output.ToString();
    }

    public static string UrlDecode(string str)
    {
      return UrlDecode(str, Encoding.UTF8);
    }

    private static char[] GetChars(MemoryStream b, Encoding e)
    {
      return e.GetChars(b.GetBuffer(), 0, (int)b.Length);
    }

    public static string UrlDecode(string s, Encoding e)
    {
      if (null == s)
        return null;

      if (e == null)
        e = Encoding.UTF8;

      StringBuilder output = new StringBuilder();
      long len = s.Length;
      NumberStyles hexa = NumberStyles.HexNumber;
      MemoryStream bytes = new MemoryStream();

      for (int i = 0; i < len; i++)
      {
        if (s[i] == '%' && i + 2 < len)
        {
          if (s[i + 1] == 'u' && i + 5 < len)
          {
            if (bytes.Length > 0)
            {

              output.Append(GetChars(bytes, e));

              bytes.SetLength(0);
            }

            output.Append((char)Int32.Parse(s.Substring(i + 2, 4), hexa));
            i += 5;
          }
          else
          {

            bytes.WriteByte((byte)Int32.Parse(s.Substring(i + 1, 2), hexa));
            i += 2;
          }
          continue;
        }

        if (bytes.Length > 0)
        {
          output.Append(GetChars(bytes, e));
          bytes.SetLength(0);
        }

        if (s[i] == '+')
        {
          output.Append(' ');
        }
        else
        {
          output.Append(s[i]);
        }
      }

      if (bytes.Length > 0)
      {
        output.Append(GetChars(bytes, e));
      }

      bytes = null;
      return output.ToString();
    }

    public static string UrlDecode(byte[] bytes, Encoding e)
    {
      if (bytes == null)
        return null;

      return UrlDecode(bytes, 0, bytes.Length, e);
    }

    private static int GetInt(byte b)
    {
      char c = Char.ToUpper((char)b);
      if (c >= '0' && c <= '9')
        return c - '0';

      if (c < 'A' || c > 'F')
        return 0;

      return (c - 'A' + 10);
    }

    private static char GetChar(byte[] bytes, int offset, int length)
    {
      int value = 0;
      int end = length + offset;
      for (int i = offset; i < end; i++)
        value = (value << 4) + GetInt(bytes[offset]);

      return (char)value;
    }

    public static string UrlDecode(byte[] bytes, int offset, int count, Encoding e)
    {
      if (bytes == null || count == 0)
        return null;

      if (bytes == null)
        throw new ArgumentNullException("bytes");

      if (offset < 0 || offset > bytes.Length)
        throw new ArgumentOutOfRangeException("offset");

      if (count < 0 || offset + count > bytes.Length)
        throw new ArgumentOutOfRangeException("count");

      StringBuilder output = new StringBuilder();
      MemoryStream acc = new MemoryStream();

      int end = count + offset;
      for (int i = offset; i < end; i++)
      {
        if (bytes[i] == '%' && i + 2 < count)
        {
          if (bytes[i + 1] == (byte)'u' && i + 5 < end)
          {
            if (acc.Length > 0)
            {

              output.Append(GetChars(acc, e));

              acc.SetLength(0);
            }

            output.Append(GetChar(bytes, offset + 2, 4));
            i += 5;
          }
          else
          {

            acc.WriteByte((byte)GetChar(bytes, offset + 1, 2));
            i += 2;
          }
          continue;
        }

        if (acc.Length > 0)
        {
          output.Append(GetChars(acc, e));
          acc.SetLength(0);
        }

        if (bytes[i] == '+')
        {
          output.Append(' ');
        }
        else
        {
          output.Append((char)bytes[i]);
        }
      }

      if (acc.Length > 0)
      {
        output.Append(GetChars(acc, e));
      }

      acc = null;
      return output.ToString();
    }

    public static byte[] UrlDecodeToBytes(byte[] bytes)
    {
      if (bytes == null)
        return null;

      return UrlDecodeToBytes(bytes, 0, bytes.Length);
    }

    public static byte[] UrlDecodeToBytes(string str)
    {
      return UrlDecodeToBytes(str, Encoding.UTF8);
    }

    public static byte[] UrlDecodeToBytes(string str, Encoding e)
    {
      if (str == null)
        return null;

      if (e == null)
        throw new ArgumentNullException("e");

      return UrlDecodeToBytes(e.GetBytes(str));
    }

    public static byte[] UrlDecodeToBytes(byte[] bytes, int offset, int count)
    {
      if (bytes == null)
        return null;

      int len = bytes.Length;
      if (offset < 0 || offset >= len)
        throw new ArgumentOutOfRangeException("offset");

      if (count < 0 || offset <= len - count)
        throw new ArgumentOutOfRangeException("count");

      ArrayList result = new ArrayList();
      int end = offset + count;
      for (int i = offset; i < end; i++)
      {
        char c = (char)bytes[i];
        if (c == '+')
          c = ' ';
        else if (c == '%' && i < end - 2)
        {
          c = GetChar(bytes, i, 2);
          i += 2;
        }
        result.Add((byte)c);
      }

      return (byte[])result.ToArray(typeof(byte));
    }

    public static string UrlEncode(string str)
    {
      return UrlEncode(str, Encoding.UTF8);
    }

    public static string UrlEncode(string s, Encoding Enc)
    {
      if (s == null)
        return null;

      if (s == "")
        return "";

      byte[] bytes = Enc.GetBytes(s);
      bytes = UrlEncodeToBytes(bytes, 0, bytes.Length);
      return Encoding.ASCII.GetString(bytes, 0, bytes.Length);
    }

    public static string UrlEncode(byte[] bytes)
    {
      if (bytes == null)
        return null;

      if (bytes.Length == 0)
        return "";
      bytes = UrlEncodeToBytes(bytes, 0, bytes.Length);
      return Encoding.ASCII.GetString(bytes, 0, bytes.Length);
    }

    public static string UrlEncode(byte[] bytes, int offset, int count)
    {
      if (bytes == null)
        return null;

      if (bytes.Length == 0)
        return "";
      bytes = UrlEncodeToBytes(bytes, offset, count);
      return Encoding.ASCII.GetString(bytes, 0, bytes.Length);
    }

    public static byte[] UrlEncodeToBytes(string str)
    {
      return UrlEncodeToBytes(str, Encoding.UTF8);
    }

    public static byte[] UrlEncodeToBytes(string str, Encoding e)
    {
      if (str == null)
        return null;

      if (str == "")
        return new byte[0];

      byte[] bytes = e.GetBytes(str);
      return UrlEncodeToBytes(bytes, 0, bytes.Length);
    }

    public static byte[] UrlEncodeToBytes(byte[] bytes)
    {
      if (bytes == null)
        return null;

      if (bytes.Length == 0)
        return new byte[0];

      return UrlEncodeToBytes(bytes, 0, bytes.Length);
    }

    static char[] hexChars = "0123456789ABCDEF".ToCharArray();

    public static byte[] UrlEncodeToBytes(byte[] bytes, int offset, int count)
    {
      if (bytes == null)
        return null;

      int len = bytes.Length;
      if (len == 0)
        return new byte[0];

      if (offset < 0 || offset >= len)
        throw new ArgumentOutOfRangeException("offset");

      if (count < 0 || offset < len - count)
        throw new ArgumentOutOfRangeException("count");

      ArrayList result = new ArrayList();
      int end = offset + count;
      for (int i = offset; i < end; i++)
      {
        char c = (char)bytes[i];
        if (c == ' ')
          result.Add((byte)'+');
        else if ((c < '0' && c != '-' && c != '.') ||
            (c < 'A' && c > '9') ||
            (c > 'Z' && c < 'a' && c != '_') ||
            (c > 'z'))
        {
          result.Add((byte)'%');
          int idx = ((int)c) >> 4;
          result.Add((byte)hexChars[idx]);
          idx = ((int)c) & 0x0F;
          result.Add((byte)hexChars[idx]);
        }
        else
        {
          result.Add((byte)c);
        }
      }

      return (byte[])result.ToArray(typeof(byte));
    }

    public static string UrlEncodeUnicode(string str)
    {
      if (str == null)
        return null;

      StringBuilder result = new StringBuilder();
      int end = str.Length;
      for (int i = 0; i < end; i++)
      {
        int idx;
        char c = str[i];
        if (c == ' ')
        {
          result.Append('+');
          continue;
        }

        if (c > 255)
        {
          result.Append("%u");
          idx = ((int)c) >> 24;
          result.Append(hexChars[idx]);
          idx = (((int)c) >> 16) & 0x0F;
          result.Append(hexChars[idx]);
          idx = (((int)c) >> 8) & 0x0F;
          result.Append(hexChars[idx]);
          idx = ((int)c) & 0x0F;
          result.Append(hexChars[idx]);
          continue;
        }

        if ((c < '0' && c != '-' && c != '.') ||
            (c < 'A' && c > '9') ||
            (c > 'Z' && c < 'a' && c != '_') ||
            (c > 'z'))
        {
          result.Append('%');
          idx = ((int)c) >> 4;
          result.Append(hexChars[idx]);
          idx = ((int)c) & 0x0F;
          result.Append(hexChars[idx]);
          continue;
        }

        result.Append(c);
      }

      return result.ToString();
    }

    public static byte[] UrlEncodeUnicodeToBytes(string str)
    {
      if (str == null)
        return null;

      if (str == "")
        return new byte[0];

      return Encoding.ASCII.GetBytes(UrlEncodeUnicode(str));
    }

    /// <summary>
    /// Decodes an HTML-encoded string and returns the decoded string.
    /// </summary>
    /// <param name="s">The HTML string to decode. </param>
    /// <returns>The decoded text.</returns>
    public static string HtmlDecode(string s)
    {
      if (s == null)
        throw new ArgumentNullException("s");

      bool insideEntity = false; // used to indicate that we are in a potential entity
      string entity = String.Empty;
      StringBuilder output = new StringBuilder();

      foreach (char c in s)
      {
        switch (c)
        {
          case '&':

            output.Append(entity);
            entity = "&";

            insideEntity = true;
            break;
          case ';':
            if (!insideEntity)
            {
              output.Append(c);
              break;
            }

            entity += c;
            int length = entity.Length;
            if (length >= 2 && entity[1] == '#' && entity[2] != ';')
              entity = ((char)Int32.Parse(entity.Substring(2, entity.Length - 3))).ToString();
            else if
              (length > 1 && entities.ContainsKey(entity.Substring(1, entity.Length - 2)))
              entity = entities[entity.Substring(1, entity.Length - 2)].ToString();
            output.Append(entity);
            entity = String.Empty;
            insideEntity = false;
            break;
          default:
            if (insideEntity)
              entity += c;
            else
              output.Append(c);
            break;
        }
      }
      output.Append(entity);
      return output.ToString();
    }

    /// <summary>
    /// Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.
    /// </summary>
    /// <param name="s">The HTML string to decode</param>
    /// <param name="output">The TextWriter output stream containing the decoded string. </param>
    public static void HtmlDecode(string s, TextWriter output)
    {
      output.Write(HtmlDecode(s));
    }

    /// <summary>
    /// HTML-encodes a string and returns the encoded string.
    /// </summary>
    /// <param name="s">The text string to encode. </param>
    /// <returns>The HTML-encoded text.</returns>
    public static string HtmlEncode(string s)
    {
      if (s == null)
        throw new ArgumentNullException("s");

      StringBuilder output = new StringBuilder();

      foreach (char c in s)
        switch (c)
        {
          case '&':
            output.Append("&amp;");
            break;
          case '>':

            output.Append("&gt;");
            break;
          case '<':

            output.Append("&lt;");
            break;
          case '"':

            output.Append("&quot;");
            break;
          default:
            if ((int)c > 128)
            {

              output.Append("&#");

              output.Append(((int)c).ToString());

              output.Append(";");
            }
            else

              output.Append(c);
            break;
        }
      return output.ToString();
    }

    /// <summary>
    /// HTML-encodes a string and sends the resulting output to a TextWriter output stream.
    /// </summary>
    /// <param name="s">The string to encode. </param>
    /// <param name="output">The TextWriter output stream containing the encoded string. </param>
    public static void HtmlEncode(string s, TextWriter output)
    {
      output.Write(HtmlEncode(s));
    }

    #endregion // Methods
  }
}

